When gas prices are high, it can tough for many drivers to simply fill up the tank. But waiting until your gas tank is almost empty before a fill-up could end up costing you even more -- and, in fact, it can be dangerous.

A new survey found that every year 827,000 drivers ignore their car's warning light, causing them to run out of gas and break down. On top of that, 25% of drivers believe they can make it another 40 miles once the light turns on, and two million drivers say they almost always drive with the light permanently on, usually hoping to find cheaper gas.

There are several reasons you shouldn't drive around on empty -- or close to empty.

First, the fuel guage isn't always accurate. In fact, how precise your car's gauge is relies on a variety of factors, including your driving style and your car's fuel economy. According to experts, you should consider it more as an estimate -- rather than an exact measurement -- of how far you'll make it before running out of gas.

Plus, allowing the level of gas in the tank to run low can damage your car.

According to Consumer Reports, the gas in your car "acts like a coolant for the electric fuel-pump motor, so when you run very low, this allows the pump to suck in air, which creates heat and can cause the fuel pump to wear prematurely and potentially fail."

And the repair could cost a couple hundred dollars -- more than what it would have cost you to fill up the tank. Also, "if there is dirt in the fuel tank, it could lead to blocking the fuel filter" -- leading to another expensive repair.

In addition to potentially costly repairs to your car, driving on a low tank can be dangerous. If the car suddenly stops running, you could be stranded in a deserted area, or in the middle of a busy highway. And with many cars, the airbags don't deploy if the car is turned off, putting you, and any passengers, in a more dangerous situation.